Quarterly report pursuant to Section 13 or 15(d)

Description of Business and Basis of Preparation - Additional Information (Detail)

v3.20.2
Description of Business and Basis of Preparation - Additional Information (Detail)
3 Months Ended 9 Months Ended
Oct. 01, 2020
USD ($)
shares
Jul. 17, 2020
shares
Jul. 16, 2020
shares
Apr. 10, 2020
USD ($)
shares
Apr. 09, 2020
USD ($)
Dec. 12, 2019
USD ($)
$ / shares
shares
Sep. 30, 2020
USD ($)
shares
Sep. 30, 2019
USD ($)
shares
Sep. 30, 2020
USD ($)
shares
Sep. 30, 2019
USD ($)
shares
Jun. 30, 2020
shares
Dec. 31, 2019
USD ($)
shares
Jun. 30, 2019
shares
Dec. 31, 2018
shares
Organization Consolidation And Presentation Of Financial Statements Disclosure [Line Items]                            
Accumulated deficit             $ (283,902,000)   $ (283,902,000)     $ (271,428,000)    
Cash and cash equivalents             29,494,000   29,494,000     $ 41,920,000    
Shelf registration maximum equity offering price                 322,800,000          
Common stock issued, net of expenses             $ 1,909,000 $ 3,206,000 $ 4,578,000 $ 9,761,000        
Reverse stock split, ratio     0.1                      
Common stock, shares authorized (in shares) | shares   100,000,000 250,000,000       100,000,000   100,000,000     100,000,000    
Common stock, shares issued (in shares) | shares   10,508,302 105,083,291       10,798,119   10,798,119     9,741,372    
Common stock, shares outstanding (in shares) | shares   10,508,302 105,083,291       10,798,119   10,798,119     9,741,372    
Stock issued during period as result of reverse stock splits | shares   0 0                      
New Jersey Technology Business Tax Certificate Transfer (NOL) Program                            
Organization Consolidation And Presentation Of Financial Statements Disclosure [Line Items]                            
Maximum selling value of unused net operating losses and research and development tax credit to profitable tax payers.                 $ 15,000,000          
Income tax benefit from sale of unused net operating losses and research and development tax credit                 3,100,000          
Amount received from the program                 $ 9,900,000          
Option to Purchase Common Stock                            
Organization Consolidation And Presentation Of Financial Statements Disclosure [Line Items]                            
Options expiration date           2020-01                
Common Stock                            
Organization Consolidation And Presentation Of Financial Statements Disclosure [Line Items]                            
Common stock issued, net of expenses (in shares) | shares             315,939 279,911 647,504 768,658        
Common stock issued, net of expenses             $ 0 $ 0 $ 0 $ 0        
Common stock, shares outstanding (in shares) | shares             10,798,119 5,736,242 10,798,119 5,736,242 10,478,927 9,741,372 5,452,011 4,797,198
December 2019 Public Offering                            
Organization Consolidation And Presentation Of Financial Statements Disclosure [Line Items]                            
Common stock issued, net of expenses (in shares) | shares           3,888,888                
Number of warrants issued to purchase common stock (in shares) | shares           3,888,888                
Share price (in dollars per share) | $ / shares           $ 9.00                
Common stock issued, net of expenses           $ 32,500,000                
Underwriters | Warrant liability                            
Organization Consolidation And Presentation Of Financial Statements Disclosure [Line Items]                            
Number of warrants issued to purchase common stock (in shares) | shares           583,333                
Number of warrants exercised | shares           583,333                
October 2020 Shelf Registration                            
Organization Consolidation And Presentation Of Financial Statements Disclosure [Line Items]                            
Shelf registration maximum equity offering price                 $ 200,000,000.0          
Subsequent Event | October 2020 Shelf Registration                            
Organization Consolidation And Presentation Of Financial Statements Disclosure [Line Items]                            
Shelf registration maximum equity initial offering price $ 200,000,000.0                          
Shelf registration maximum equity offering price 200,000,000.0                          
Subsequent Event | October 2020 Shelf Registration | Sales Agreement | Common Stock                            
Organization Consolidation And Presentation Of Financial Statements Disclosure [Line Items]                            
Shelf registration maximum equity offering price $ 50,000,000.0                          
Number of Shelf Registration Equity Sold | shares 0                          
Maximum | Option to Purchase Common Stock                            
Organization Consolidation And Presentation Of Financial Statements Disclosure [Line Items]                            
Number of options not exercised | shares           583,333                
Maximum | Underwriters                            
Organization Consolidation And Presentation Of Financial Statements Disclosure [Line Items]                            
Option to purchase shares of common stock | shares           583,333                
April 2020 Note Purchase Agreement | 6.0% Senior Convertible Notes due 2026                            
Organization Consolidation And Presentation Of Financial Statements Disclosure [Line Items]                            
Date of issuance and sale of notes         Apr. 09, 2020                  
Face amount         $ 10,000,000.0                  
Interest rate         6.00%                  
Aspire Capital | Common Stock Purchase Agreement                            
Organization Consolidation And Presentation Of Financial Statements Disclosure [Line Items]                            
Sale of common stock at sole discretion       $ 20,000,000.0                    
Number of purchase aggregate shares of common stock | shares       1,956,547                    
Percentage of common stock outstanding       19.99%                    
Common stock issued, net of expenses (in shares) | shares             125,000   125,000          
Aspire Capital | Common Stock Purchase Agreement | Maximum                            
Organization Consolidation And Presentation Of Financial Statements Disclosure [Line Items]                            
Sale of common stock at sole discretion       $ 20,000,000.0                    
Percentage of common stock outstanding       19.99%